Furnace



Dec. 15 ,1925

lrlwventor: Wesley F'. Massey.

Filed J His Attorney.

Patented Dee 15,- 1925.

UNITED STATES' 1,566,224 PATENT OFFICE.

WESLEY IF. MASSEY, lF BAIiLSTON SPA, NEW YORK, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

FURNACE.

Application led .Tune 1,2, 1324. Serial No. 719,688.

To all whom tymay concern.'

Be it known vthat I, WESLEY F. MAssEY, a citizen of the United States,residing at Ballston Spa, in the county of Saratoga, State of New York,have invented certain new and useful Improvements in Furnaces,

vof which the following is a specification.

' desirable that the furnace should be sealed in such manner as not onlyto assure the maintenance of the vacuum but also to allow the furnace tobe easily and quickly opened and closed. One method of sealing thefurnace of this type is to secure the cover in place by means ofsuitable bolts o r lag screws. With this method, however, 1t is atedious operation to open and close the furnace.

In carrying out my invention I seal the furnace with a fusible material,which may be solder, and provide means for melting the sealing materialwhen the furnace 1s to be opened or closed.

cover 11.

For a more complete understanding of my invention reference should bemade to the accompanying drawing inwhich Fig. 1 isV an elevation view insection of an electric furnace embodying my invention, while Fig. 2 is asection view along the line 2-2 of F ig. l looking in the direction ofthe arrows.

Referring to the drawing, I have shown my invention in one form asapplied to an electrically heated vacuum furnace although my inventionhas obvious application to furnaces in general regardless of the methodof heating. The furnace comprises a cylindrical casing or tank 10provided with a This casing is made yof a nonporous material ofsufficient strength to permit its being evacuated. It is preferably madeof a metal, such as steel. Inside the casing is an electric heatingresistor 12, shown as a wire wound in the form of a helix on a support13 made of insulating material. Between the heating resistor and thetank 10 is a cylindrical member V1l made l of suitable heat insulatingmaterial by means of which direct radiation of heat from the resistor tothe tank is prevented. The members 13 and 14 may be made of alumdum. Theends or terminals 15 and v16 of the heating resistor are brought outthrough the sideof the tank 10 through suitable insulating and packingbushings 17 and 18, whereby the terminals are lelectrically insulatedfrom the tank and leakage around the terminals is prevented.

My present invention relates more particularly to the provision of aseal between the cover 11 and the tank. For this purpose an annulartrough-like receptacle 20 is secured on the outside of the tank at theupper end thereof,` forexample by brazing or welding so as to provideiatight joint between the receptacle and the tank. The cover 1,1 isprovided with a peripheral `flange 2l which extends downward when thecover is in place into the receptacle 20. In the receptacle is a mass ofsuitable fusible sealing material 22 which may be a. metal, such as asolder.

- Associated withthe receptacle is an electric heating unit 23 by meansof which the sealing material 22 may be melted to permit the cover to beput in place or removed in closing and opening the furnace. ing unit maybe of any suitable form and is shown as comprising a resistanceconductor embedded in compacted insulating material in a metallicsheath, for example, asidescribed and claimed'in U. S. Patent No.1367341 to Charles C.' Abbott. The heating unit is bent in the shape ofa ring and is placed in the bottom of the receptacle 20. Terminals 24and 25 of the heating unit are brought out through the side' of thereceptacle for connection to a suitable electrical supply s ource.

As thus constructed and arranged, it will be observed that when thecover is in place the flange 21 is embedded in the fusible sealingmaterial 22 which thus forms a tight joint between the cover and thetank. In closing the furnace the fusible material is rst melted by meansof the heating unit 23, after which the cover is simply put in place andthe sealing material allowed to cool. IVhere the sealing material is asolder, a soldered joint is thus formed between the cover and tank. Thisprovides a very etli- This heatcient leak-proof joint and one which canbe easily and quickly made. In opening the furnace it is necessary onlyto first melt the sealing material by means of the heating unit wherebythe cover is released and can be removed. It will be understood that thearticles to be heated are placed inside the inner insulating cylinder13. The furnace chamber may be evacuated through the pipeQ provided forthat purpose which leads to a suitable evacuating pump. (Not shown).

The outer envelope of the furnace cou- .sistingof the tank with itscover 11 is preferably cooled by submerging it in waterin a tanlLQT. Theterminals and 16 are brought out through thc wall of the tank 27 throughsuitable packing and insulating bushings 28 and 29. Tater may beintroduced into the tank through a water inlet pipe 30 at the bottom, anoverflow pipe 31 being provided at the top. lVhen it is dcsred to openthe furnace afterthe complelion of the heating the water is drained outof the tank Q7 below the upper level of the tank 10 and preferably belowthe receptacle 2O so that the receptacle will not be cooled by the Waterwhile the sealing materlal is being heated.

While I have described my invention as embodied in concrete form and asoperating in a specific manner in accordance with the provisions of thepatent statutes, it should be understood that I do not limit myinvention thereto, since various modifications thereof will suggestthemselves to those skilled in the art without departing'from the byLetters Patent of the United States is l 1. The combination with anelectric furnace, of a fusible material for sealing said furnace, areceptacle for said fusible material, and an electric heating unit insaid receptacle whereby the `sealing material may be melted to open saidfurnace.

2. The combination with an electric furnace, of a cover for saidfurnace, a mass of fusible material forming a tight joint between saidfurnace and cover, a receptacle for said fusible material, and anelectric heating unit in said receptacle whereby the fusible materialmayy be melted to release said cover.

The combination with an electric-furnace provided with a cover, of areceptacle around the mouth of said furnace into which the coverextends, a fusible metal in-said receptacle. sealing,r said furnace',and an electric heating unit in said receptacle, whereby the metal maybe fused to permit the -removal of said cover.

4. The combination with an electric furnace provided with a metalliccasing, a cover for said casing, a mass of solder forming a sealed ]o|ntbetween sald casing and cover,

a receptacle for said solder, and a.- sheathed

